Chain crowd shovel excavator



E. H. LICHTENBERG ET AL CHAIN CROWD SHOVEL EXCAVATOR Sept. 29, 1936.

2 Sheeis-Sheet 1 Filed Feb. 15, 1935 [my H. l/Cl/TENBER EH14. L- FEW/vans- WILL/17M f5TEFFE/V.

p 1936- E. H. LICHTENBERG ET'AL CHAIN CROWD EXCAVATQR v Filed Feb. 13, 1935 2 Sheets-Sheet 2 [:RICH H. .gc/v TEA/55x6. f/v/L L IRENE/75. WILL/HM'E 57EFFE/V.

Patented Sept. 29, 1936 UNITED STATES PATENT OFFICE William F.

Steffen, Milwaukee, Wis., as-

signors to Koehring Company, Milwaukee,

Wis., a corporation Application February 13,1935, Serial No. 6,372

6 Claims. (01. 214- 135) The present invention appertains to what are commonly known to those versed in the art as shovel excavators or excavating machines. Such machines comprise generally atraction base, a body or cab structure mounted thereon containing the driving or operating machinery, a boom till and means for raising and lowering the boom, and a shovel dipper connected by a dipper stick or handle with the boom. The operating machinery used for the operations of thrusting out or crowding the dipper to its work, and retracting or racking in the dipper, so called, are controlled from the operating machinery either by cable drives, chain drives, or shaft and gear drives.

Since the boom is a pivoted boom to permit of its raising and lowering actions, the transmission devices for conveying the driving forces of the operating machinery to the dipper stick or handle must be designedto communicate said forces in some way through the supporting means for the boom, past the chute of the boom, and up to a point intermediate the ends of the boom where the dipper stick or handle has shiitable or sliding connection with the boom for actuating purposes.

The present invention contemplates a novel chain drive for transmitting forces from the operating drum mechanism on the body of the machine to the dipper stickior crowding out and retracting the latter with its dipper.

Chain drive means for the purpose stated have been proposed heretofore, as exemplified for instance in the patent of Hanson, No. 1,808,409, issued June 2, 1931, wherein one drive chain connected with the reversing drum mechanism is connected to a transmission shaft at the axis of the boom and a second drive chain carries off the drive from said shaft to the dipper stick, being directly connected to the shipper shaft on the boom.

The aim of the present invention has been to design a single chain drive for the purpose stated, and this has required the employment of novel means for guiding the chain, or flexible member equivalent thereto, as it passes from the operating drum mechanism to the foot of the boom, thence to the shipper connection with the dipper stick or handle, and back from the last connection past the foot oi the boom again to the drum mechanism. The problem involved lies in the fact that the boom is required to be raised and lowered in the various operations of the shovel dipper. Obviously, the raising and lowering of the boom varies the positions of the upper and lower runs or loops of the chain when a. single chain is trained downwardly from the drum mechanism of the shovel body around devices at the foot of the boom and upwardly to the intermediate portion of the boom where connection of the chain for driving action with respect to the dipper stick or handle is made.

The present invention contemplates provisions such that during the elevating or lowering adjustments of the boom, guide members associated with the boom, and its support adjacent to the foot portion of the latter, operate to maintain a substantially uniform tension upon the driving chain or flexible member, so that no undue looseness interfering with the proper operation of said chain will be incurred, notwithstanding that the boom may be adjusted to any position between its upper limit and lower limits of working movement.

The invention involves a unique mounting of the said guide means which comprise upper and lower sprocket gears engaging the upper and lower bights or loops of the chain, respectively, which mounting involves a supporting of the guide member for the lower loop below the axis of the boom and a supporting of the guide member for the upper loop above the said axis at a substantially greater distance therefrom than is the point of support of the lower member. The peculiar mounting means just referred to involves the peculiar location of the guide member axes at opposite sides of the boom pivotal axis, which location has been determined empirically but involves definite principles as to the arrangement of the guide members and mode of training the driving chain thereover in such a way that the looseness of the upper loop or blght of the chain, tending to be created by the action of lowering the boom to elongate or cause the upper and lower sides of the chain to approach alignment, will be taken up by the moving adjustment of the upper guide member relatively to the lower member and relatively to the axis of the boom, thereby to maintain the chain under a substantially uniform tension under all conditions of adjustment of the boom in its working range of movement upwardly and downwardly.

Certain preferred embodiments of the invention are illustrated in the accompanying drawings, but I do not wish to be limited thereto since a modification of the specific constructions provided may be employed.

In the accompanying drawings- Figure 1 illustrates a side elevational view of a shovel excavator or shovel crane embodying the invention, dotted lines illustrating the dipper and dipper handle in upraised position fully extended,

and full lines showing same in lower digging position fully extended.

Figure 2 is a fragmentary diagrammatic view illustrating primarily the locations of the drum mechanism for driving the chain or flexible actuating device, and the relative locations of the guide members or idler sprocket gears, the pivotal axis or the boom, and the disposition of the upper and lower loops of the drive chain when the boom is at different adjustments in its working range upwardly and downwardly.

Figure 3 is a fragmentary plan view showing more clearly the method of mounting the guide members or sprockets upon the foot of the boom.

Figure is a side elevation of the parts illustrated in Figure 3, the body of the boom partially broken away.

Figure 5 is a sectional View of the mountings oi the upper guide member.

Figure 6 is a fragmentary view showing a modiiied form of the invention wherein the driving chain, instead of being endless as in Figure i, has ends directly attached to the dipper stick.

The shovel excavator or crane construction as depicted in Figure 1 of the drawings is very largely of the conventional type. It comprises the socalled swing body A adapted to rotate upon a turntable B supported upon endless traction belts C diagrammatically shown. At one end of the swing body A is the boom D adapted to be raised and lowered by a hoisting cable means including the cable E. On the boom D is supported the dipper stick or handle l equipped. at its outer end with the dipper 2 and adapted to be crowded out, and retracted, after the manner of ordinary implements or this character. The boom D is pivoted to the swing body A at the axis 3, see Figures 1. and 3. The dipper stick it is equipped with the usual racks 6. on the side members of said dipper stick, with which engage the shipper pinions 5 fixed to a shipper shaft 6 to which movement is imparted by a drive chain l, the mounting of which is the primary feature oi the present invention. The shipper shaft ii carries a sprocket gear 8 about which the chain l, which is preferably a sprocket chain, passes and is inter-engaged therewith.

As customary in machines of the type of the invention, the driving mechanism on the swing body A includes a reversible operating drum 9, on which is carried an operating sprocket gear it about which the chain :1 also passes and with which it is inter-engaged.

We now come to the peculiar feature of the invention, which lies in the mounting of the chain 1 in relation to the guiding means therefor located at the foot of the boom. This guiding means includes an upper idler sprocket gear H and a lower idler sprocket gear l2. The mounting of these sprocket gears H and l2 is peculiar the lower gear l2 being supported about an axis member or shaft it which is located in fixed position, said axis member l3 being supported by oflsetting brackets l4 having the bearings lit to receive said shaft l3. It is notable that the axis of the shaft I3 is located a short distance below the axis 3 for the boom.

The upper sprocket gear ll may be mounted adjustably by having its supporting shaft lb carrled in adjustable bearings l1 shiftable in a plane somewhat transverse to the axis of the boom D by means of the adjusting screw devices 88 and the lock nuts i9 threaded thereon. Screws it pass through openings in the boom foot member 26 and are held against longitudinal displaceaosaooo ment by means oi other nuts iii ihe detail construction of the screws and their adjusting means is immaterial because any suitable means of this type for adjusting the bearing members l'l might be availed of. The bearing members ll slide in suitable guides formed in the boom foot casting or member 2d previously referred to. The sprockct gear ll is spaced a substantial distance from the gear it).

It will be observed, of course, that the axis shaft to of the gear ii is mounted at the opposite side or" the axis 8 for the boom D from that at which the axis shaft it of the gear l) is largely disposed.

In reference to the mode of training the chain l around the gears M and i2, it is notable that the upper bight or loop of the chain passes beneath and is inter-engaged with the gear ii, and the lower bight or loop of the chain l passes underheath and is inter-engaged with the gear l2. The space between the gears ll and it? must be sumcient that under any conditions of adjustment of the boom D upwardly and downwardly within its working range of utility, the upper loop or bight ofthe chain l will not engage with the teeth of the sprocket gear 52, or preferably should not.

In general disposition the sides or bights of the chain ll may be said to extend at an angle from a medial point, providing what is characterized herein as an upper loop or bight and the lower loop or bight, both together having an L-shaped arrangement when the boom D is at and near the upper limit of its working adjustment. When the boom D is lowered by operation of the boom hoisting cable E, the tendency of the angularly extending portions of the chain l is to move toward alignment. Even when the boom D is at its lower limit of movement, however, alignment of the angularly extending portion. of the chain 71 is not achieved.

It will be apparent that by reason of the arrangement of the upper and lower loops or bights of the chain i when the boom D is raised from the position shown in Figure l, the tendency of the upper bight will,ordinarily be to assume a looseness, while the lower bight or loop will become tight. However, the said upper bight or loop of chain l under the above conditions is acted upon by a shifting of the sprocket gear ll counterclockwise backwardly about the axis of the boom 3 incident to the raising of said boom whilst there is a slight shifting of the sprocket gear l2 counterclockwise forwardly in reference to saidaxls 3 at the same time. By reason of the location of the axis members it and i3 at properly determined distances eccentric to the exist of the boom, in such a manner that distance a is equal to the distance 7) (Fig. 2), the shifting of the sprocket gears H and i2 relatively to the axis 3 and to the portions or the chain 5 with which they engage maintains the chain bights or loops substantially under the same tension at all times, and thus looseness is not.

permitted to disturb such tension.

The only purpose in providing the adjusting means to, ll, l8, i9, 20, 2! is to take up wear on the chain as its life continues, there always being I a certain amount of such wear by reason of the heavywork which chain of this kind performs in an excavating implement for the purposes mentioned.

In Figure 2 there is illustrated diagrammatical 1y a reversible driving member 9 and a portion of the chain or flexible driving element l as trained under the gears H and i2. Also. this figure shows the degree of shifting of the axis of the gear l2 on a rearward and upward are generated about the pivot point of the boom, said are disposed eccentrically below said pivot point. Likewise there is illustrated the range of movement of the upper gear Ii on an arc generated about the pivot point of the boom as the center, but located substantially a greater distance from the pivot point than the arc in which the axis of the lowergear i2 moves. It has been determined that the arrangement of the axes of the parts D, II, and I2, as illustrated in the drawings and described above, is such that a substantially uniformtem' -sion will be maintained upon the flexible driving ness of only is created in the chain i when the boom D is lowered to its maximum extent. This amount of looseness does not under practical conditions become at all objectionable from an engineering and practical standpoint, for obvious reasons.

In the construction of the invention in Figure 6, instead of using an endless chain as in the Figure l illustration, the upper ends oi the flexible member or chain lid are trained about two pulleys or guiding sprockets 22 and 23 carried by the boom and directly attached to the dipper stick. The upper loop or bight oi the chain 1a is secured permanently by suitable'iastening means to the upper end portion of the dipper stick 9 as shown at lit, while the outer end of the lower bight orloop of the chain in is attached at 25 to the lower end of the dipper stick adjacent to the point where it supports the dipper 2. At such lower end 25 a suitable adjusting device may be availed of to perform the function of the adjusting means l6, l1, l8, namely, to take up such looseness as may be created in the chain or member To incident to wear only. So far as the function of the parts It and I2 is concerned, this function, in reference,to maintaining the member '17 or "lo under tension, is equally existent when the driving chain for the dipper takes the form of the endless construc-. tion of Figure 1, or takes the rangement in Figure 6.

The construction of the invention as set forth in the above permits that all the machinery-necessary for the shovel attachment is mounted on the shovel boom' and is therefore a part of the attachment, which, in commercial use is quite an advantage in that it is not necessary to mount extra machinery and parts on the swing body A.

In other words, when the base of the machine,

the swing body and traction devices, is equipped with a crane boom, it may easily be converted into a shovel by detaching the crane boom and replacing the same by a shovel attachment, as

the only additional part that would go on the swing body A is the sprocket gear l0.

It will be seen therefore from the above exbetween the center line or neutral axis a. (Figure 2) and the loops of chain 1- are equal, while form of the ar the distance between pivots l8 and I3 remains also equal under all conditions of operation.

The position of the gears II and I2 with re- 'spect to the boom pivot 3 is such that the lowest points of the pitch lines of said gears are at substantially equal distancesfrom the horizontal axis of the boom pivot.

Having thus described our invention, what we claim as new and desire to secure by Letters Patent of the United States, is-

' i. In an excavating shovel of the type described, comp'rising a body, a boom pivoted to the body, hoisting means for raising and lowering the boom, a dipper stick on the boom, driving mechanism on the body for the actuation of the dipper stick to crowd out and retract the same, including reversible means for such purpose, in combination-with a single flexible member connected with said reversible means of the driving mechanism and leading past the foot of the boom and operatively connected for actuating the dipper stick, guide means on the foot of the boom and comprising spaced guide elements, under one of which an upper loop portion of the flexible member is trained, and under the other of which a lower loop portion. of the flexible member is trained, the axis of the upper guide elementbeing disposed at one side of the pivotal axis of the boom and the axis of the lower guide element being disposed at the opposite side of the pivotal axis of the boom, the positions of the axes of the guide elements being such that the distances between the upper loop portion and the neutral axis through the boom pivot, and between the lower loop portion and said neutral 3X15, are maintained substantially equal at all positions of working operation of the boom to thereby maintain a substantially uniform tension in the flexible member.

2. In an excavating shovel of the type described, comprising a body, a boom pivoted to the body, hoisting means for raising and lowering the boom, a dipper stick on the boom, driving mechanism on the body for the actuation of the dipper stick to crowd out and retract the same,

including reversible means for such purpose, in combination with a drive. chain operativelyconnected-with the reversible driving means of the said driving mechanism, spaced parts of said drive chain being formed in upper and lower loops extending downwardly from the reversible driving means to the foot of the boom and thence upwardly along the boom to points oioperative connection with the dipper stick for actuation of the latter, guide means for the upper and lower .the upper loop of the chain and the neutral axisthrough the boom pivot, and between the lower loop of the chain and said neutral axis, and thereby aiiord a substantially uniform tension in the chain in all working positions of the boom.

3. In an excavating shovel comprising a body having operating mechanism including a reversible driving member, aboom pivoted to the body,

and a dipper stick on sad coom movalole for crowding out and retracting movements, hoisting means for raising and lowering the boom, and a driving connection between said delving member and the dipper stlcl; comnrlsing a chain looped about and interengaged with the driving member of said operating mechanism and passing down= warclly therefrom past the foot of the boom and thence upwardly to the dipper sticl: point oi connection thereof in the form of upper and lower loops or side elements of the chain, an guide means on the foot portion of the boom including ugoper sprocket beneath which the upper loop of the chain passes, and lower sprocket beneath which the lower loop of the chain passes, the axes of the said sprockets -einglocated eccentric to the pivotal of the boom and opposite sides of said EJZlS, and the lower sprocket being relatively close to the pivotal axis of the boom and the upper sprocket being a substantially greater distance away from the pivotal axis of the boom than the lower sprocket,

l. in an excavator shovel comprising a body, operatic mechanism thereon including a reversible d1 sprocket gear, a boom pivoted at its foot to the body, a dipper stick on the boom, and a driving chain for crowding out and retracting he dippe stick by connection therewith, said driving chain being looped about the said driving sprocket gear and passing downwardly in upper and lower portions to the foot of the boom and then passing upwardly to a point intermediate the ends of the boom where said looped portions are connected to actuate the dipper stick, and means for maintaining the loops of the chain under a substantially uniform tension irrespective of the up and down adjustment of the boom about its pivotal axis, and comprising guide sprocket gears located at opposite sides of the pivotal axis of the boom, one guide sprocket gear being arranged so that the upper loop of the chain passes beneath the same, and the other guide sprocket gear being disposed so that the lower loop of the chain passes beneath it, the guide sprocket gear which engages the upper loop of the chain being located a distance from the pivotal axis of the boom many times the distance between the axis of the other guide sprocket gear and said pivotal axis of the boom, whereby the action of raising and lowering the boom is such s to cause the of the said guide sprocket gears to in opposite directions.

5. in an excavating shovel, comprising, in com-- lcination, a oody, a boom oted to said body, means to raise and lower the boom, a dipper sticl: carrying excavating instrumentalities operatively connected with said "coon driving means on he swing body, driven means carried by 9 com and engaging the dipper same, a single flexible power transmission means interconnecting said d ing and driven ons and comprising an nope; 1d a lower loop having angtdarly-disposed left and right nor s, and guide members rotative on said boom and cenea'tli which the respective upper and lower loops oi flexible transmission means are trained guiding the flexible power transmission the members b i g oo centers of the rotative gt sitioned with respect to center of pivot in such a manner as to maint tances between a center line passin' in. boom pivotal axis parallel to the le' t portions oi the upper and lower loops of the flexible powei' transmitting means substantially equal all o= sitions of working operation of the looom to by maintain the flexible power transmlttng means taut.

6. in an excavating shovel, comprising, in combinatlon, a body, a boom, a boom pivot connecting the boom with said body, means to raise and lower the boom, a dipper stick carrying excavating instrumentalities operatively connected with said boom, driving means on the body, driven means carried by the boom and engaging the dipper stick for operating the same, a single power transmission chain interconnecting said driving means and driven means, and a plurality of gears fixed to said boom and rotatable thereon for guiding said chain, said gears lowest points of their pitch lines at substantially equal distances from said boom pivot so as to maintain the power transmission chain substantially taut under all operating positions of the boom.

e boom ERICH H. LICHTENBERG. Ell/ 1L L. TRANAAS. WIELIAEVI F. STEI' FriN.

stick for operating the 1 being positioned with the L 

